Network Layers | Cloud Computing and Mobile

Networking

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Data link layer
Data link layer is the second layer in the OSI model, it is responsible for maintain the flow of
data. A data link layer is responsible for coding the bits of data and framing it into different
layer. It is used to establish a connection between devices that are present on the same
network. It transfers the bit of data frames from physical layer to network layer and vice
versa. It offers a reliable way of communication by assuring that information remains secure.
While transmitting the data from one layer to another, it is encrypted so that only authorised
user access the data (Xu, Li, Li, Zhang & Muntean, 2015).
The basic functions of data link layer are controlling the flow and access of data. It is also
responsible for physical addressing and framing of data packets. Data link layer has few
issues associated with it, like it requires a traffic identifying mechanism so that flow of data
could be monitored. It offers a well-defined service interface on the network by dealing with
all the transmission errors (Lopacinski, Nolte, Buechner, Brzozowski & Kraemer, 2015).
Additionally, it can be said that data link layer is responsible for both logical link control and
media access control.

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(Source : https://masror.com/data-link-layer-osi-model/)
This layer is responsible for packing the data by encapsulating it into the frames. It also
maintains the synchronization of data at times of data transfer. Data link layer ensures flow
control by enabling the machines to exchange the information at high speed. Data link layers
transfers the frames from one layer to another it also prevent traffic jam.
Transport layer
Transport layer is used for server applications and allow access to information to user. It also
grants the access of multiplexing by allowing multiple users to access the information at the
same time (Rescorla, 2018). The service of transport layer is gained using datagram protocol.
The UDP packet of transport layer covers the address of source and destination. The UDP
packet also covers the checksum bit that is used to check whether the data is securely
transferred or not (Zhao, Sexton Park, Baure, Nino & So, 2015). If the checksum bit does not
match it can be found that some bugs have hit the system. Some of the functions that are
offered by transport layer are that it offers connection oriented communication by using
internet protocol and datagram protocol. In case of transport layer packets are not lost as they
are checked by using checksum bit that keeps an idea about arrival of packets from sender
and receiver.